1. Field of the Invention.
This invention relates to the field of location-based services, and more particularly to the field of location-based services involving portable electronic facilities.
2. Description of the Related Art.
Location systems have been developed for determining and tracking the locations of the users of mobile devices such as cellular phones, including global positioning systems (GPS), as well as various triangulation systems that use cellular telephone signals, broadcast television signals, or the like. Dead reckoning systems also exist for determining locations of devices based on movement in reference to a set of known coordinates. However, to date the uses of such systems have been limited. A need exists for improved systems for using location-based information for a variety of purposes.